[vlc-devel] Re: files encoded to x264 with mencoder fail to stream with vlc

[David Liontooth]

Måns Rullgård wrote:
> David Liontooth <liontooth at cogweb.net> writes:
>   
>> In my version, mencoder uses x264 core 43, and ffmpeg core 44. Could
>> this make the difference?
>>     
> That could make a lot of difference.  x264 v43 and earlier wrote an
> incorrect frame rate.  FFmpeg from the same day as x264 v44 or later
> have the corresponding fix and a workaround for streams encoded with
> old x264 versions.  Using an old ffmpeg with a new x264 could make
> video play at the wrong frame rate.
>   
Thanks! Marillat just released an updated version of mplayer, so I got 
to test this -- and it still fails to stream.
The aspect ratio is wrong at the receiving end -- as if it's using width 
for height? It's all blurred and blocky.

Strings now shows,

x264 - core 45 - H.264/MPEG-4 AVC codec - Copyleft 2005 - 
http://www.videolan.org/x264.htm
l - options: cabac=1 ref=4 deblock=1:0:0 analyse=0x3:0x113 me=hex 
subme=6 brdo=0 mixed_ref
=0 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 chroma_qp_offset=0 
slices=2 nr=0 bfram
es=3 b_pyramid=0 b_adapt=1 b_bias=0 direct=1 wpredb=0 bime=0 keyint=250 
keyint_min=25 scen
ecut=40 rc=2pass bitrate=667 ratetol=1.0 rceq='blurCplx^(1-qComp)' 
qcomp=0.60 qpmin=10 qpm
ax=51 qpstep=2 cplxblur=20.0 qblur=0.5 ip_ratio=1.40 pb_ratio=1.30
> One difference I see here is that mencoder used B-frames, while ffmpeg
> didn't.  B-frames in AVI is a Bad Idea (tm).
>   
In mencoder, I was using this --

mencoder -tv 
driver=v4l2:device=/dev/video$DEV:fps=30000/1001:chanlist=us-bcast:\
audiorate=32000:adevice=/dev/dsp$DEV:input=0:amode=1:normid=4:width=384:height=288 
\
-ovc x264 -x264encopts 
threads=2:bitrate=500:bframes=3:subq=6:me=2:frameref=4:8x8dct \
-oac mp3lame -lameopts cbr:br=64 -endpos $TIM -o $DIR/$FIL.avi tv:// > 
/dev/null

Setting "bframes=0" slowed the encoder; should I just leave it out? What 
are sensible values
to use for mencoder? I don't have to use the avi wrapper -- what would 
you recommend? All
we need is for the files to play well in VLC on Linux, OSX, and Windows 
-- a bonus would
be if they could be read into Quicktime on OSX.

I tested again without "bframes=3" and now the aspect ratio is correct, 
but the stream is still completely messed up. Strings show,

x264 - core 45 - H.264/MPEG-4 AVC codec - Copyleft 2005 - 
http://www.videolan.org/x264.htm
l - options: cabac=1 ref=4 deblock=1:0:0 analyse=0x3:0x113 me=hex 
subme=6 brdo=0 mixed_ref
=0 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 chroma_qp_offset=0 
slices=2 nr=0 bfram
es=0 keyint=250 keyint_min=25 scenecut=40 rc=2pass bitrate=669 
ratetol=1.0 rceq='blurCplx^
(1-qComp)' qcomp=0.60 qpmin=10 qpmax=51 qpstep=2 cplxblur=20.0 qblur=0.5 
ip_ratio=1.40

So bframes causes problems with aspect ratio for VLC when streaming, but 
there's some other factor that messes up the picture.
Again, the file plays fine locally, and for some reason ffmpeg-encoded 
files stream flawlessly.

I'm very grateful for help with this -- we have a large project on the 
horizon and need to know what works.

David





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